I think this is the essence of the debate. Flaws should not be immaterial... but I don't view it as "bending over backwards" to make them part of the game. Both edges and flaws help to define your character, but they are also part of the GMs job to make them matter. Taking an Edge that never comes up is wasted points; taking a flaw that never comes up is bonus points. And it's up to the GM to make sure, especially in the case of flaws, that they come up.If it doesn't impede your ability when the spotlight is on, it's not a real flaw.